How Much Soil in Containers Do I Need

How Much Soil in Containers Do I Need?

Last Updated on August 16, 2022 by Real Men Sow

The amount of soil in containers depends on the size of the pot. There are many sizes of containers and growing pots. When it comes to container sizes, there aren’t many standards. Measure across the pot’s top from one end to determine its size. The volume of a pot can vary because some pots have a longer length than others and some have squat sides.

How to Estimate Soil in Containers

It is best to estimate how much soil in containers you will need before filling. The volume of a container will often be measured in liquid quarts and liters. However, you can only buy dry soil (potting soil is not liquid). One quart of dry soil is equivalent to approximately 1 1/8 quarts. It is important to consider soil compression when deciding how much soil you will purchase. This happens most often by moistening the soil and pressing it into the pot. The soil can be compressed to add 15 to 20% more dry soil in containers. Remember that you will move some soil around roots when you transplant a plant.

Make sure to note down the pots that you own and what soil they need. You will quickly be able to estimate how much soil is needed for potting plants.

How Much Soil in Containers Depends on the Container Type and Size

Standard Clay Pots and Plastic Nursery Pots

  • 4 inch pot (10 cm) = 1 pint (0.5L)
  • 5-6 inch pot (13-15 cm) = 1 quart (1L) = 0.03 cu. ft.
  • 7-8 inch pot (18-20 cm) = 1 gallon (4L) = 0.15 cu. ft.
  • 8.5 inch pot (22 cm) = 2 gallon (7.5L) = 0.3 cu. ft.
  • 10 inch pot (25 cm) = 3 gallon (11L) = 0.46 cu. ft.
  • 12 inch pot (30 cm) = 5 gallon (19L) = 0.77 cu. ft.
  • 14 inch pot (36 cm) = 7 gallon (26L) = 1 cu. ft.
  • 16 inch pot (41 cm) = 10 gallon (38L) = 1.5 cu. ft.
  • 18 inch pot (46 cm) = 15 gallon (57L) = 2.3 cu. ft.
  • 24 inch pot (61 cm) = 25 gallon (95L) = 3.8 cu. ft.
  • 30 inch pot (76 cm) = 30 gallon (114L) = 4.6 cu. ft.

Hanging Baskets

  • 10 inch (25 cm) = 5.5 dry quarts (6L) = 0.21 cu. ft.
  • 12 inch (30 cm) = 7.9 dry quarts (8.4L) = 0.3 cu. ft.
  • 14 inch (36 cm) = 13.9 dry quarts (15.3L) = 0.5 cu. ft.

Plant Bowls

  • 8 inch (20 cm) = 1.9 dry quarts (2L) = 0.07 cu. ft.
  • 10 inch (25 cm) = 3.7 dry quarts (4L) = 0.14 cu. ft.
  • 12 inch (30 cm) = 5.5 dry quarts (6L) = 0.21 cu. ft.
  • 14 inch (36 cm) = 8.4 dry quarts (9.2L) = 0.29 cu. ft.
  • 16 inch (41 cm) = 12.0 dry quarts (13.2L) = 0.46 cu. ft.
  • 18 inch (46 cm) = 18.8 dry quarts (20.7L) = 0.73 cu. ft.
  • 21¾ inch (55 cm) = 31.2 dry quarts (34.3L) = 1.21 cu. ft.

Oval Planters

  • 12 inch (30 cm) = 3.8 dry quarts (4.1L) =0.14 cu. ft.
  • 16 inch (41 cm) = 7.3 dry quarts (8L) = 0.28 cu. ft.
  • 20 inch (51 cm) = 9.4 dry quarts (10.3L) = 0.36 cu. ft.

Square Planters

  • 12 inch (30 cm) = 11.2 dry quarts (12.3L) = 0.48 cu. ft.
  • 15 inch (38 cm) = 23.0 dry quarts (25.3L) = 0.89 cu. ft.

Window Boxes

  • 24 inch (61 cm) = 11.7 dry quarts (12.8L) = 0.45 cu. ft.
  • 30 inch (76 cm) = 15.6 dry quarts (17.1L) = 0.6 cu. ft.
  • 36 inch (91 cm) = 19.7 dry quarts (21.6L) = 0.76 cu. ft.

Strawberry Pots

  • 5 gallon = 14 dry quarts (15.4L) = 0.54 cu. ft.
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